Hardness of a material is indicative of various physical qualities and characteristics of the material such as resilience, durability, uniformity, tensile strength, abrasion resistence, and other characteristics.
Prior methods of testing hardness of material include the Brinell hardness test in which a hardened ball is pressed into the sample material for a selected length of time and then the diameter of the indentation is measured and correlated to the amount of pressure used. The Rockwell hardness test is similar, but the depth of penetration of the ball is measured. Measurement of hardness of rubber like materials is on a Shore durometer scale which includes an "A" scale.